Drainless humidifier with water level sensing

ABSTRACT

A housing is permanently connected to a water supply of a building and includes an evaporative water panel allowing water to flow downwardly and wick upwardly. A circulating device is provided for directing air from the building through the water panel. A reservoir is positioned in the housing for supporting the water panel and holding excess water deposited from the water panel. A water distributor is supplied for moving water from the water supply to a top of the water panel. A water control arrangement is responsive to the water level therein for automatically controlling the flow of water to the water panel to provide a desired humidity level in the building.

FIELD OF THE INVENTION

This invention relates generally to humidifiers, and more particularly,control of evaporation in a humidifier used in conjunction with afurnace or heating system and connected to the plumbing system of abuilding. Humidifiers of this type typically use an air circulationarrangement to move air across a water-soaked evaporative pad. Thehumidifier is associated with the furnace or heating system so that thehumidifier moist air can be combined with the warm, generally dry,heated air and distributed through a building.

BACKGROUND OF THE INVENTION

Humidifiers generally characterized by a housing having an evaporativewater panel constructed of slit and expanded non-wicking paper,removably disposed in a reservoir at the bottom thereof. The housingalso has a mechanical float valve which is connected to a water supplyof a heated building. A water feed tube is connected to the mechanicalfloat valve for supplying water to a distributor from which water flowsby gravity down through the water panel. Air is forced through the waterpanel and the air evaporates water on the water panel, so thathumidified air is delivered to the building.

Such humidifiers typically employ a device such as a humidistat, forestablishing predetermined humidity set point and reading humiditylevels in the building. The humidistat is connected in a circuit with apump and operates, in the presence of low humidity, to automaticallydeliver water from a lower reservoir to the top of the water panel anddownwardly therethrough. Some of the water evaporates from the waterpanel and is air blown to provide humidity to the building. Theremainder of the water collects in the reservoir at the bottom of thewater panel. As the reservoir level drops due to loss of evaporatedwater, the float valve opens to allow water in from supply and maintainsreservoir level. The pump recirculates water from the reservoir over thenon-wicking water panel. This cycle continues as long as the humidistatreads low humidity. Once the humidity set point is reached, the circuitis opened and water flow ceases.

There also exist drum-type humidifiers wherein a motor and gear systemis used to rotate a drum in a reservoir of standing water.

While such designs generally provide the desired humidification, therearises problems in the cost, noise, maintenance, electrical power needsand reliability associated therewith. Another problem with these designsis that the reservoir remains filled no matter if humidity is needed ornot. As a result, there is a possibility of undesirable bacteria, algae,fungus, mold, etc.

Accordingly, it is desirable to provide a humidifier which is responsiveto the changing water level in the reservoir. It is also desirable toprovide a humidifier which is more economical in cost, runs morequietly, requires less maintenance and lessens the electrical powerneeds.

SUMMARY OF THE INVENTION

It is one object of the present invention to provide a humidifieremploying a float switch which responds to the water level in thereservoir.

It is also an object of the present invention to provide a humidifierwhich employs a wicking-type evaporative water panel.

It is a further object of the present invention to provide a humidifierwhich allows for complete evaporation of water in the reservoir.

It is an additional object of the present invention to provide ahumidifier which operates normally without the need for a drain.

Still another object of the present invention is to provide a humidifierwhich is easier to manufacture and maintain and which is safer tooperate.

In one aspect of the invention, a housing is permanently connected to awater supply of a building and includes an evaporative water panelallowing water to flow downwardly and wick upwardly. A circulationdevice is provided for directing air from the building to the waterpanel. A reservoir is positioned in the housing for supporting the waterpanel and for holding excess water deposited from the water panel. Awater distributor is provided for moving the water from the water supplyto the top of the water panel. A water control arrangement is responsiveto the water level within the reservoir for automatically controllingthe flow of water to the water panel to provide a desired humidity levelin the building. The water panel is comprised of a multi-layer, slit andexpanded, wicking paper. In the preferred embodiment, the aircirculating device includes a blower associated with a furnace, or a fanbuilt integrally into the humidifier and the reservoir includes firstand second vertical walls connected to a horizontal base wall. The watercontrol arrangement includes a solenoid valve connected to a water levelsensor. The water level sensor is preferably comprised of a float switchhaving a float member provided with a magnet therein, and a reed switchconnected to the solenoid valve. The float member and magnet arepositioned above the horizontal base wall of the reservoir, and the reedswitch is aligned with the magnet and positioned below the reservoir,isolated from any water contact therewith. In the preferred embodiment,the reservoir includes a tubular chamber and the float member is aball-shaped float.

The invention also contemplates various other methods for movablymounting the float member. In one embodiment the reservoir includes apost having one end of the hinge slidably attached thereto and anotherend of the hinge attached to the float member. In another alternativeembodiment, the reservoir includes a post having one end of a solidfolding hinge attached thereto and the other end of the solid foldinghinge attached to the float member. In yet another alternativeembodiment, the reservoir includes a set of posts upon which the floatmember is slidably mounted. In still another alternative embodiment, thereservoir includes a post provided with a pivoted edge having one end ofa float arm pivotally attached. thereto and another end of the float armattached to the float member. In still another alternative embodiment,the reservoir includes a horizontal ledge having one end of a flexiblehinge attached thereto and another end of the flexible hinge attached tothe float member.

The water distributor is a tube extending from the solenoid valve to anoutlet nozzle and a weir-type distributor trough which is positionedover the water panel. The water distributor may also take the form of afeed tube extending from the solenoid valve to an outlet manifoldpositioned over the water panel. An overflow tube is molded directly tothe side of the reservoir for receiving any water which overflows thereservoir. The humidifier typically includes a humidistat forestablishing a desired humidity level.

In another aspect of the invention, the humidifier has a device forcontrolling the flow of water to an evaporative water panel positionedin a reservoir and allows water to flow downwardly and wick upwardly.The humidifier also has a humidistat for establishing a desired humiditylevel and an operative circulating means for directing air through thewater panel. The humidifier includes a water level sensor which isassociated with the reservoir and which is responsive to the water leveltherein to alternatively open and close a circuit to control the flow ofwater to the water panel. With this construction, when the water levelin the reservoir is low, the circuit is closed to deliver water to thewater panel such that some water evaporates from the water panel and theremainder collects in the reservoir. A rising water level in thereservoir causes the sensor to open the circuit, stopping waterdelivery, humidification continuing as water wicks upwardly through thewater panel. The falling water level in the reservoir causes the sensorto close the circuit, delivering further water to the panel, thereservoir eventually drying out once the desired humidity is reached.The humidistat forces the circuit open when the desired humidity levelis reached so as to prevent the water cycling on and off indefinitely.Stoppage of the circulating means will have the same effect.

Various other features, objects, and advantages of the invention will bemade apparent from the following description taken together with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode presently contemplated of carryingout the invention.

In the drawings:

FIG. 1 is a side cross sectional view of a humidifier embodying thepresent invention;

FIG. 1A is a view of an alternative distributor in the form of an outletmanifold;

FIG. 2 is a fragmentary view of a reservoir and float switch arrangementof the humidifier of FIG. 1 with a low water level as taken on line 2—2of FIG. 1;

FIG. 3 is a cross sectional view showing an overflow tube moldeddirectly to the reservoir;

FIG. 4 is a diagrammatic view showing a typical start-up mode for thehumidifier of FIG. 1;

FIGS. 5 and 6 are diagrammatic views depicting a humidification cyclefor the humidifier of FIG. 1;

FIGS. 7 and 8 are diagrammatic views depicting a dry-down mode for thehumidifier of FIG. 1; and

FIGS. 9-13 are alternative embodiments of various arrangements formovably mounting a portion of the float switch.

DETAILED DESCRIPTION OF THE INVENTION

As seen in FIG. 1, a humidifier 10 embodying the present inventionincludes a base portion 12 and cover 14 which define a housing that ismounted on a portion of the furnace or on a wall or ceiling. Baseportion 12 includes an evaporative water panel 16 preferably formed of aslit and expanded construction of wicking paper mounted in a frameworkor scale control 18. Base portion 12 also includes a water feed tube 20having one end which supplies water to a nozzle 22 and distributor 24for the water panel 16. Another end of feed tube 20 is joined to asolenoid valve 26 which controls the flow of water through the feed tube20. Solenoid valve 26 is, in turn, permanently connected to the plumbingor water supply 28 of a building. As depicted in FIG. 1A, distributor 24may also take the form of a manifold 25 for conducting watertherethrough. The humidifier 10 also includes air circulation means suchas a furnace blower fan 30 (FIG. 4) for directing air through the wettedwater panel 16. A humidistat 31 (FIG. 4) is commonly used to set adesired humidity set point.

In accordance with the invention, part of the scale control 18 isprovided with either an integral or separate small reservoir 32 forholding excess water supplied to the water panel 16. As seen best in thepreferred embodiment of FIGS. 2, reservoir 32 includes a tubular chamber34 having a main well formed by a base wall 36 and first and secondvertical walls 38,40. A water level sensing float member 46 takes theform of a ball float 47 having a magnet 48 mounted internally within andsupported on base wall 36 when the water level is low. Depending on thewater level in the reservoir well, the ball 47 will be enabled to moveup or down in chamber 34. Referring to FIG. 3, molded to the side of thereservoir 32 is an overflow tube 54 for receiving any water whichoverflows the reservoir 32. Reference numeral 51 indicates the normalwater level in the reservoir 32. If solenoid valve 26 fails and thewater level goes too high, water drains over the lip 53 of overflow tube54 and into a drain before it floods over the top of reservoir 32.Attached to the base portion 12 beneath base wall 36 and betweenvertical walls 38,40 is a reed switch 62 which is suitably electricallyconnected to the solenoid valve 26. As seen in FIG. 2, the reed switch62 is aligned beneath the magnet 48 in ball float 47. As will beunderstood more fully hereafter, the magnet 48 in the ball float member47 cooperates with the reed switch 62 to define a float switch 70. Withwater in the reservoir well at the low level, the float switch 70 has aclosed position which will allow the solenoid valve 26 to remain open.With water in the reservoir well at a high level, the float switch 70has an open position which will close the solenoid valve 26.

Referring now to FIGS. 4-8, the operation of the humidifier 10 will nowbe described. It can be seen that a transformer 72, a furnace sensor 74,solenoid valve 26, humidistat 31, and float switch 70 are seriallyconnected in a circuit and are responsive to the on/off condition of themotor-driven furnace fan 30. When furnace fan 30 is “on”, sensor 74closes, humidistat 31 senses low humidity when the water level in thereservoir 32 is low, and magnet 48 in float member 46 holds reed switch62 closed, so that the float switch 70 is closed (FIG. 4). A circuit iscompleted to the solenoid valve 26 which opens and supplies water to thedistributor 24 at the top of the humidifier 10. Water drains from thedistributor 24 and runs downwardly through the water panel 16. Somewater evaporates from the water panel 16 to provide humidity to thebuilding. The remainder of the water collects in the reservoir 32 at thebottom of water panel 16. As the water level rises (FIG. 5), the floatmember 46 lifts the magnet 48 away from the reed switch 62 to a pointwhere the reed switch opens a circuit and causes the solenoid valve 26to close. Humidification continues as water now wicks upwardly (FIG. 5)from reservoir 32 into the water panel 16. This action is made possibleby purposely constructing the water panel 16 with the slit and expandedwicking paper. Eventually, the water level drops (FIG. 6) and the magnet48 again closes the circuit to solenoid valve 26, so that more waterenters the humidifier 10. This cycle continues (FIG. 7) as long as thefurnace fan 30 runs and the humidistat 31 reads low humidity. When thehumidity set point has been satisfied, the reservoir 32 will dry out(FIG. 8) because water continues to wick into the water panel 16 andevaporates while the humidistat 31 holds the circuit open and preventsmore water from entering the humidifier.

It should be appreciated that the humidifier 10 of the present inventionprovides a magnetic level sensing device in which the float member 46and magnet 48 are placed in a separate assembly from reed switch 62.This feature allows for easy replacement of the water panel 16 withouthaving to disconnect any wires. It also maintains the electrical switchoutside the water containing reservoir 32 which is safer and easier tomanufacture because waterproofing is not needed. By downsizing thereservoir 32 and eliminating the pump of prior humidifiers. there is areduction in cost, noise, and electrical power needs. Because thepresent invention is designed to dry out the reservoir 32, undesirablebiological growths are limited. Whereas the prior art relied onnon-wicking paper for allowing downward migration of moisture, thepresent invention by virtue of the wicking paper also enables upwardmigration of moisture which aids the evaporation.

It should also be noted that while in the preferred embodiment the waterlevel sensor has float member 46 in the form of a ball with a magnet 48which floats in a tubular channel of the reservoir 32, there are otherarrangements contemplated to perform the same result. In the alternativeembodiment in FIGS. 9, a flexible hinge 49 has one end connected to afloat member 46 and another end having a mechanical pivot point, such asthat of a stepped vertical shaft 76 in a hole formed in the flexiblehinge 49. In FIG. 10, a solid articulating or folding hinge 78 has oneend connected to the float member 46 and another end connected to avertical post 80. In FIG. 11, float member 46 is mounted for sliding upand down movement on a pair of vertical posts 82,84. In FIG. 12, arocker arm 86 has one end connected to float member 46 and another endpivotably mounted on a pointed edge of a vertical post 90.

In FIG. 13, a forward portion of the reservoir 32 includes a steppedcompartment 92 having a main well formed by a base wall 94 and first andsecond vertical walls 96,98. The shorter vertical wall 98 is formed withan outwardly projecting horizontal ledge 100 which turns into a thirdvertical wall 102. A water level sensing float member 104 having amagnet 106 mounted internally within is supported on the base wall 94when thew water level is low. A flexible hinge 108 has one end 110secured to the top of float member 104 and has another end 112 anchoredto the ledge 100. A bottom wall 114 has a raised boss 116 creating aninterior space for a reed switch 118. Bottom wall 114 is also formedwith a set of upright ribs 120,122 which function to locate verticalwalls 96,98 therebetween with the base wall 94 of stepped compartment 92resting upon an upper horizontal wall 124 of the boss 116. The ribs120,122 provide alignment of the reservoir 32 and its float member 104,and magnet 106 with the reed switch 118.

It is also noted that other means may be used to sense water, such aswith electrical conductivity sensors, or optical, sound wave or weightsensing arrangements.

It should be mentioned that the reservoir 32 can be provided, ifdesired, with a downwardly depending conduit used to lead water away toa drain. This is a desirable safety feature which is useful should thesolenoid valve 26 become jammed open or otherwise held open due to anelectrical failure. However, in the intended operation, all watersupplies would be evaporated and the drain would not be used.

While the invention has been described with reference to a preferredembodiment, those skilled in the art will appreciate that certainsubstitutions, alterations and omissions may be made without departingfrom the spirit thereof. For example, in humidifiers having an internalfan, the furnace sensor 74 would not be used, and the fan would becontrolled via a relay added to the circuit.

We claim:
 1. A humidifier comprising: a housing permanently connected toa water supply of a building and including an evaporative water panelallowing water to flow downwardly and wick upwardly; circulating meansfor directing air from the building through the water panel; a reservoirpositioned in the housing for supporting the water panel and holdingexcess water deposited from the water panel; a water distributor formoving the water from the water supply to a top of the water panel; andwater control means responsive to the water level therein forautomatically controlling the flow of water to the water panel toprovide a desired humidity level in the building, wherein the reservoirincludes first and second vertical walls connected to a horizontal basewall, wherein the water control means includes a solenoid valveconnected to a water level sensor, and wherein the water level sensor iscomprised of a float switch having a float member provided with a magnettherein and a reed switch connected to the solenoid valve, the floatmember and magnet being positioned above the horizontal base wall of thereservoir, and the reed switch being aligned with the magnet andpositioned below the reservoir isolated from any water contacttherewith.
 2. The humidifier of claim 1, wherein the water panel iscomprised of multi-layer, slit and expanded, wicking paper.
 3. Thehumidifier of claim 1, wherein the circulating means includes a blowerassociated with a furnace.
 4. The humidifier of claim 1, wherein thecirculating means is a fan built integrally into the humidifier.
 5. Thehumidifier of claim 1, wherein the float member is movable relative tothe reservoir mounted thereto.
 6. The humidifier of claim 1, wherein thereservoir includes a tubular chamber and the float member is aball-shaped float.
 7. The humidifier of claim 1, wherein the reservoirincludes a support member having one end of a flexible hinge attachedthereto and another end of the flexible hinge attached to the floatmember.
 8. The humidifier of claim 1, wherein the reservoir includes apost having one end of a solid folding hinge attached thereto and theother end of the solid folding hinge attached to the float member. 9.The humidifier of claim 1, wherein the reservoir includes at least onepost upon which the float member is slidably constrained.
 10. Thehumidifier of claim 1, wherein the reservoir includes a post providedwith a pivoted edge having one end of a float arm pivotably attachedthereto and another end of the float arm attached to the float member.11. The humidifier of claim 1, wherein the water distributor is a feedtube extending from the solenoid valve to a weir-type distributor. 12.The humidifier of claim 1, wherein the water distributor is a feed tubeextending from the solenoid valve to an outlet nozzle positioned overthe water panel.
 13. The humidifier of claim 1, wherein the waterdistributor is a feed tube extending from the solenoid valve to anoutlet manifold positioned over the water panel.
 14. The humidifier ofclaim 1, including an overflow tube attached to the side of thereservoir for receiving any water which overflows the reservoir.
 15. Thehumidifier of claim 1, including a humidistat for establishing a desiredhumidity level.